Fax (short for “facsimile”) refers to technology for transferring documents, files or images over a communications network. Although fax technology dates back to the 1800's and its underlying principles today remain similar to those from long ago, fax only gained widespread popularity and global market penetration in recent decades with the modernization of communications equipment and networks. Such improvements allowed fax technology to develop and expand to an extent that “fax machines” became ubiquitous devices used by millions to routinely transmit documents, files or images quickly, easily and reliably anywhere in the world and in turn led to widespread acceptance of and reliance upon fax technology by both the private and public sectors as a viable—and in most cases preferred—alternative to the more time consuming and expensive process of sending documents via postal mail. These and other factors caused fax technology to become an extremely important and lucrative worldwide industry.
With the more recent surge in popularity of electronic mail (“email”), however, there were concerns as to whether fax technology would continue to be relevant, let alone profitable. These fears have proven to be unfounded, as fax continues to flourish and is predicted to remain a telecommunications fixture for many years to come. Fax technology, may adapt, however, to be implemented with new techniques as new technology becomes available. Most notably, as fax technology became widespread, faxes were being transmitted on or via the Public Switched Telephone Network (PSTN). And although the PSTN is still by far the most widespread telephone network used for fax worldwide and is poised to remain as such for years to come, there has been increasing interest in and usage of Internet Protocol (IP) based networks for fax, particularly in the last several years.
There is little doubt that IP-based networks hold exciting promise in terms of what they may provide in addition to or above and beyond PSTN networks. However, as many have already observed, migration from the PSTN to IP-based networks likely will not be entirely seamless, requiring changes and/or adjustments in order to enable legacy PSTN technology, such as fax, to be used in the same or different ways on IP networks.
To date, those who send faxes over IP networks do so by utilizing a call control protocol (e.g., SIP or H.323) to negotiate into faxing modes between gateways located on both ends (sending/receiving) of a fax transmission. The fax is transmitted as an audio stream (via RTP) or as a fax session (via T.38, a T.30-based network wrapper) over the IP network; in both cases, the negotiations of these transport layers use non-standard IP ports within the so-called “Dynamic” (as opposed to so-called “Well Known” or “Registered”) IP port ranges. Problems arise, for example, due to interactions between different networks with different network security rules, which can prevent the usage of these media communication ports and, in turn, block the establishment of these fax media sessions. One could attempt to obviate these problems to enable real-time fax by opening all of the more than 15000 Dynamic ports. However, making these ports available is not a practical solution, since the relevant portion of the IP Network would be vulnerable to security breaches and/or malicious attacks and content. In other words, although real-time fax transmission is possible on IP networks as presently architected, it would bring with it very real risks that would outweigh the benefits it would provide.
Various “store and forward” systems have been deployed in an attempt to work around Fax over IP (FoIP) network issues and that would not result in vulnerability to these types of security issues. However, such systems are unable to provide real-time fax functionality, since they buffer fax documents and retransmit them on behalf of users at a later time, thus employing two or more call legs and failing to provide real-time notification to originating fax devices as to whether the fax sessions were successful or not. This non-real-time fax facility presents a number of problems, including the inability to meet requirements established for traditional fax devices or various worldwide industry, compliance and/or governmental mandates.
Therefore, a need exists for technology that allows for real-time facsimile (or other non-fax communications) to occur via IP-based networks to fully utilize the benefits of such IP-based networks, yet while also not leaving IP Networks vulnerable to security issues and while at least preserving, if not improving upon, the overall experience of existing technology and conventional methodology.